Your Vice Is a Locked Room and Only I Have the Key

Il tuo vizio è una stanza chiusa e solo io ne ho la chiave is a movie starring Edwige Fenech, Anita Strindberg, and Luigi Pistilli. A series of murders are committed near the estate of a degenerate author and his wife.
Oliviero is a drunk, burned-out writer who amuses himself by hosting orgies at his grand country manor and humiliating his wife Irina. When a number of women are murdered in grisly fashion, Oliviero becomes a prime suspect.